The Kendo Music Store sample app has an example of an ASP.NET WebAPI controller reading a posted file (an image in this case, but file contents doesn't matter) and saving it to the file system: ImagesController.cs
You could do something similar; read the file contents off the ASP.NET request, and do whatever processing you want.
The HTML and Javascript that set up the Kendo upload widget is in: storemanager-index.js
And finally a little bit of documentation from the Kendo Music Store tutorial docs: Album Art Upload With The Kendo Upload Widget